Currently, locksets applied to bags generally only use coded locks. In the case that the coded lock is used, no key is required, and thus the coded lock is very convenient in use, and consequently a user does not need to worry about the problem that the key is lost or forgotten. However, during the use of the coded lock, the user needs to remember the password. If the coded lock is not used for a long time, the user may forget the password of the coded lock. In the case, the coded lock must be unlocked by force, and then may be damaged.
Moreover, along with the development of the economy, people have more opportunities to go out and carry more and more items. Therefore, when going out, people tend to carry longer and larger bags. In general, a coded lock is arranged on one side of a lower casing of a bag and a lock hook is arranged in the middle or lock hooks are arranged at both ends of a corresponding side face of an upper casing of the bag. The bag is locked via the engagement of the lock hook(s) and the coded lock. As the bag has certain flexibility, if the upper casing and the lower casing of the bag are fixedly connected with each other only through the lock hook in the middle, both sides of the bag can be easily pried up by foreign objects, and then items can be stolen. If the upper casing and the lower casing of the bag are fixedly connected with each other through the lock hooks at both ends, the central section of the bag may be pried up.